The present invention relates to a hydrodynamics retarder having a rotor blade wheel and a stator blade wheel arranged in a common housing, and more particularly to such a retarder wherein the stator blade wheel is shiftable eccentrically with respect to the rotor blade wheel.
A hydrodynamic retarder of the above type is known from Federal Republic of Germany Patent 31 13 408 which is equivalent to U.S. Pat. No. 4,474,270 issued Oct. 2, 1984 to Klaus Vogelsang for an ADJUSTABLE HYDRODYNAMIC BRAKE. That retarder serves as an energy converter in a wind driven power unit in order to convert the energy of the wind into heat, preferably with an interposed heat exchanger. It is necessary to adapt the characteristic curve of the retarder to the characteristic of the prime mover, for instance the wind driven power unit. In the known retarder, this adaptation is effected by a device which enables the stator blade wheel to be adjusted radially into an eccentric position with respect to the rotor blade wheel. The stator blade wheel is for this purpose fastened firmly eccentrically on a shaft so that the eccentricity can be brought about upon the rotation of the shaft relative to the rotor blade wheel. Upon rotation of the shaft bearing the stator blade wheel, the rotor and stator blade wheels can come into alignment or onto a common axis with each other in one shaft position. It is known to provide a linear guide for the stator blade wheel for enabling the eccentric repositioning of the two blade wheels.
If the retarder operates together with a wind driven power unit, there is cooperation of two fluid flow machines having the same basic characteristics, namely a course of the developed and the absorbed power which is parabolic with respect to the speed of rotation. In the known retarder, this circumstance enables the regulation to be limited to a fixed setting of a maximum value for the braking torque or the braking power of the retarder. Due to its own characteristics, the retarder consumes only a small amount of power when the wind driven power unit can develop only a small amount of power. Further adjustment for operation is not necessary, aside from totally emptying the operating fluid from the brake housing, for instance, for reasons of safety.
In addition, there are known possibilities for operating the retarder with different conditions of operation via a pressure control to influence the toroidal work chamber that is enclosed by the stator and rotor blade wheels. Depending upon the desired condition of operation, for instance, constant braking torque over a large range of speeds of rotation, then it is also to be taken into account that a larger profile diameter for the retarder is necessary. This is a negative influence for the use of such retarders in motor vehicles, particularly with regard to the structural size and the weight of the retarders.